The Circulation Mill, Superfluid Helium-3 Variant: A Cryogenic Source of Axial Spin-Current Circulation

Design variant of the Circulation Mill (DOI 10.5281/zenodo.24100552) using spin-polarised superfluid helium-3 in its B phase in a 15.7 cm3 annular channel at 0.40 mK. Polarisation 0.332 is prepared by brute-force polarisation of a solid precursor at 8.0 T and 10 mK followed by rapid melting. Computed (SIMULATED, NOT MEASURED) performance: T1 = 318 s, T2 = 83.1 s, circulation quantum 6.62e-8 m2/s, fractional error 0.0372 per quantum, refrigeration load 20.5 nW against 100 nW assumed available. No conversion to a torsion angle is claimed. All numbers come from the accompanying compute.py script and its results files. Sole author: William Alexander Aldred, ORCID 0009-0000-1215-577X. CC BY 4.0. AI use disclosed in the paper: Dave, an AI system, produced the design and computation.